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Assessment of spatial memory
There are a variety of tasks that psychologists use to measure spatial memory on adults, children and animal models. These tasks allow professionals to identify cognitive irregularities or in adults and children and allows researchers to administer varying types of drugs and or lesions in participants and measure the consequential effects on spatial memory. The Corsi Block Tapping Task Also known as the Corsi Span Test, this psychological test is commonly used to determine the visual-spatial memory span and the implicit visual-spatial learning abilities of an individual.Mammarella, I.C., Pazzaglia, F., & Cornoldi, C. (2008). Evidence of different components in children’s visuospatial working memory. British Journal of Developmental Psychology, 26, 337-355.Corsi, P. M. (1972). Human memory and the medial temporal region of the brain, Dissertation Abstracts International, 34(02), 891. Participants sit with nine wooden 3x3 cm blocks fastened before them on a 25 x 30 cm baseboard in a standard random order. The experiment taps a sequence pattern onto the blocks which participants must then replicate. The blocks are numbered on the experimenters’ side to allow for efficient pattern demonstration. The sequence length increases each trial until the participant is no longer able to correctly replicate the pattern. The test can be used to measure both short-term and long-term spatial memory, depending on the length of time between test and recall. The test was created by Canadian neuropsychologist Phillip Corsi, who modeled it after Hebb’s digit span task by replacing the numerical test items with spatial ones. On average most participants achieve a span of five items on the Corsi span test and seven on the digit span task. Visual Pattern Span Similar to the Corsi block tapping test but regarded as a more pure test of visual short term recall.Della Sala, S., Gray, C., Baddeley, A., & Wilson, L. (1997). The Visual Patterns Test: A new test of short-term visual recall. Feltham, Sufolk: Thames Valley Test Company. Participants are presented with a a series or matrix patterns that have half their cells coloured and the other half blank. The matrix patterns are arranged in a way that is difficult to verbally code forcing the participant to rely on visual spatial memory. Beginning with a small 2 x 2 matrix participants copy the matrix pattern from memory into an empty matrix. The matrix patterns are increased in size and complexity at a rate of two cells until the participant's ability to replicate them breaks down. On average, participant's performance tends to break down at sixteen cells. Pathway Span Task This task is designed to measure spatial memory abilities in children. The experimenter asks the participant to visualize a blank matrix with a little man. Through a series of directional instructions such as forwards, backwards, left or right the experimenter guides the participant’s little man on a pathway throughout the matrix. At the end the participant is asked to indicate on a real matrix where the little man that he or she visualized, finished. The length of the pathway varies depending on the level of difficulty (1-10) and the matrices themselves may vary in length from 2 x 2 cells to 6 x 6. Dynamic Mazes Intended for measuring spatial ability in children. With this test an experimenter presents the participant with a drawing of a maze with a picture of a man in the centre. The experimenter uses his or her finger to trace a pathway from the opening of the maze to the drawing of the man while the participant watches. The participant is then expected to replicate the demonstrated pathway through the maze to the drawing of the man. Mazes vary in complexity as difficulty increases. Radial Arm Maze Full article: Radial arm maze First pioneered by Orton and Samuelson in 1976,Olton, D.S., & Samuelson, R.J. (1976). Remembrance of places past: spatial memory in rats. Animal Behaviour Processes, 2, 97–116. the radial arm maze is designed to test the spatial memory capabilities of rats. Mazes are typically designed with a centre platform and a varying number of armsCole, M.R., & Chappell-Stephenson. (2003). Exploring the limits of spatial memory using very large mazes. Learning & Behavior, 31, 349-368. branching off with food placed at the ends. The arms are usually shielded from each other in some way but not to the extent that external cues cannot be used as reference points. In most cases, the rat is placed in the center of the maze and needs to explore each arm individually to retrieve food while simultaneously remembering which arms it has already pursued. The maze is set up so the rat is forced to return to the center of the maze before persuing another arm. Measures are usually taken to prevent the rat from using its olfactory senses to navigate such as placing extra food throughout the bottom of the maze. Moris Water Maze Full article: Morris water navigation task The Morris Water Maze is a classic for studying spatial learning and memory in rats Morris, R. G. (1981). Spatial Localization Does Not Require the Presence of Local Cues. Learning and Motivation, 12(2), 239-260. and was first developed in 1981 by Richard G. Morris whom the test is named after. The subject is placed in a round tank of translucent water with walls that are too high for it to climb out and water that is too deep for it to stand in. Additionally, the walls of the tank are decorated with visual cues to serve as reference points. The rat must swim around the pool until by chance it discovers the hidden platform just below the surface that it can climb up onto. Typically, rats swim around the edge of the pool first before venturing out into the center in a meandering pattern before stumbling upon the hidden platform however as time spent in the pool increases experience, the amount of time needed to locate the platform decreases with veteran rats swimming directly to the pool almost immediately after being placed in the water. Spatial memory performances of aged rats in the water maze predict levels of hippocampal neurogenesis full article: http://www.pnas.org/content/100/24/14385.full This study tested spatial memory in aged rats to see if there was a correlation between spatial memory and neurogenesis. The rats were injected with BrdUrd before the trial to label brain cells that already exist and the day of the trial they were injected with Ki67 to label new brain cells that formed. The results showed a negative correlation between spatial memory and new brain cells in the granule cell layer of the rats brains. This correlation is saying that the better the spatial memory (which means the shorter the distance traveled) the more new brain cells were formed. They ran the trial on young rats to compare and there was no correlation in young rats between spatial memory and new neurons. They came to the conclusion that behavioral performances in aged rats are positively correlated with cell survival and the number of new neurons in the granule cell layer. references